Safe and efficient gene transfer systems are necessary for the development of effective human somatic gene therapies. These same technologies are equally important tools for studying cell lineage and development. The Vector Core Laboratory of the Institute for Human Gene Therapy is a state of the art facility with expertise in the design, manufacture, and analysis of recombinant viral vectors for gene transfer. This technology is available to participating investigators through one of two mechanisms; as active laboratory users or through a comprehensive service provided by the Core staff. The organization of the Vector Core is tailored to accommodate a diverse array of vector needs, enabling ready access to the most advanced and thoroughly tested methods for somatic gene transfer. The specific aims of the core include': A. Provide state of the art facilities to investigators for the development of recombinant viral vectors. 1. Adenovirus * First-Generation * Second-Generation *Third-Generation 2. Adeno-Associated Virus 3. Retrovirus B. Make available large inventories of existing recombinant adenovirus and retrovirus vectors. Reporter Constructs * E. coli beta-galactosidase * Human Placenta Alkaline phosphatase C. Provide technical assistance in the design of new recombinant adenovirus, adeno-associated virus, and retrovirus vectors. D. Provide comprehensive training in the production and purification of recombinant viral vectors. E. Perform titer assays of recombinant vector stocks and biological samples obtained from preclinical and clinical studies. F. Perform helper virus assays on recombinant adenovirus, adeno-associated virus, and retrovirus stocks. G. Provide consultation on the design and application of viral vectors.